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|
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012, 2015 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
#include <sys/abd.h>
#include <sys/fs/zfs.h>
/*
* Virtual device vector for mirroring.
*/
typedef struct mirror_child {
vdev_t *mc_vd;
uint64_t mc_offset;
int mc_error;
int mc_load;
uint8_t mc_tried;
uint8_t mc_skipped;
uint8_t mc_speculative;
} mirror_child_t;
typedef struct mirror_map {
int *mm_preferred;
int mm_preferred_cnt;
int mm_children;
boolean_t mm_replacing;
boolean_t mm_root;
mirror_child_t mm_child[];
} mirror_map_t;
static int vdev_mirror_shift = 21;
/*
* The load configuration settings below are tuned by default for
* the case where all devices are of the same rotational type.
*
* If there is a mixture of rotating and non-rotating media, setting
* zfs_vdev_mirror_non_rotating_seek_inc to 0 may well provide better results
* as it will direct more reads to the non-rotating vdevs which are more likely
* to have a higher performance.
*/
/* Rotating media load calculation configuration. */
static int zfs_vdev_mirror_rotating_inc = 0;
static int zfs_vdev_mirror_rotating_seek_inc = 5;
static int zfs_vdev_mirror_rotating_seek_offset = 1 * 1024 * 1024;
/* Non-rotating media load calculation configuration. */
static int zfs_vdev_mirror_non_rotating_inc = 0;
static int zfs_vdev_mirror_non_rotating_seek_inc = 1;
static inline size_t
vdev_mirror_map_size(int children)
{
return (offsetof(mirror_map_t, mm_child[children]) +
sizeof (int) * children);
}
static inline mirror_map_t *
vdev_mirror_map_alloc(int children, boolean_t replacing, boolean_t root)
{
mirror_map_t *mm;
mm = kmem_zalloc(vdev_mirror_map_size(children), KM_SLEEP);
mm->mm_children = children;
mm->mm_replacing = replacing;
mm->mm_root = root;
mm->mm_preferred = (int *)((uintptr_t)mm +
offsetof(mirror_map_t, mm_child[children]));
return (mm);
}
static void
vdev_mirror_map_free(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
kmem_free(mm, vdev_mirror_map_size(mm->mm_children));
}
static const zio_vsd_ops_t vdev_mirror_vsd_ops = {
.vsd_free = vdev_mirror_map_free,
.vsd_cksum_report = zio_vsd_default_cksum_report
};
static int
vdev_mirror_load(mirror_map_t *mm, vdev_t *vd, uint64_t zio_offset)
{
uint64_t last_offset;
int64_t offset_diff;
int load;
/* All DVAs have equal weight at the root. */
if (mm->mm_root)
return (INT_MAX);
/*
* We don't return INT_MAX if the device is resilvering i.e.
* vdev_resilver_txg != 0 as when tested performance was slightly
* worse overall when resilvering with compared to without.
*/
/* Fix zio_offset for leaf vdevs */
if (vd->vdev_ops->vdev_op_leaf)
zio_offset += VDEV_LABEL_START_SIZE;
/* Standard load based on pending queue length. */
load = vdev_queue_length(vd);
last_offset = vdev_queue_last_offset(vd);
if (vd->vdev_nonrot) {
/* Non-rotating media. */
if (last_offset == zio_offset)
return (load + zfs_vdev_mirror_non_rotating_inc);
/*
* Apply a seek penalty even for non-rotating devices as
* sequential I/O's can be aggregated into fewer operations on
* the device, thus avoiding unnecessary per-command overhead
* and boosting performance.
*/
return (load + zfs_vdev_mirror_non_rotating_seek_inc);
}
/* Rotating media I/O's which directly follow the last I/O. */
if (last_offset == zio_offset)
return (load + zfs_vdev_mirror_rotating_inc);
/*
* Apply half the seek increment to I/O's within seek offset
* of the last I/O issued to this vdev as they should incur less
* of a seek increment.
*/
offset_diff = (int64_t)(last_offset - zio_offset);
if (ABS(offset_diff) < zfs_vdev_mirror_rotating_seek_offset)
return (load + (zfs_vdev_mirror_rotating_seek_inc / 2));
/* Apply the full seek increment to all other I/O's. */
return (load + zfs_vdev_mirror_rotating_seek_inc);
}
/*
* Avoid inlining the function to keep vdev_mirror_io_start(), which
* is this functions only caller, as small as possible on the stack.
*/
noinline static mirror_map_t *
vdev_mirror_map_init(zio_t *zio)
{
mirror_map_t *mm = NULL;
mirror_child_t *mc;
vdev_t *vd = zio->io_vd;
int c;
if (vd == NULL) {
dva_t *dva = zio->io_bp->blk_dva;
spa_t *spa = zio->io_spa;
mm = vdev_mirror_map_alloc(BP_GET_NDVAS(zio->io_bp), B_FALSE,
B_TRUE);
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c]));
mc->mc_offset = DVA_GET_OFFSET(&dva[c]);
}
} else {
mm = vdev_mirror_map_alloc(vd->vdev_children,
(vd->vdev_ops == &vdev_replacing_ops ||
vd->vdev_ops == &vdev_spare_ops), B_FALSE);
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
mc->mc_vd = vd->vdev_child[c];
mc->mc_offset = zio->io_offset;
}
}
zio->io_vsd = mm;
zio->io_vsd_ops = &vdev_mirror_vsd_ops;
return (mm);
}
static int
vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
uint64_t *ashift)
{
int numerrors = 0;
int lasterror = 0;
int c;
if (vd->vdev_children == 0) {
vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
return (SET_ERROR(EINVAL));
}
vdev_open_children(vd);
for (c = 0; c < vd->vdev_children; c++) {
vdev_t *cvd = vd->vdev_child[c];
if (cvd->vdev_open_error) {
lasterror = cvd->vdev_open_error;
numerrors++;
continue;
}
*asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
*max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1;
*ashift = MAX(*ashift, cvd->vdev_ashift);
}
if (numerrors == vd->vdev_children) {
vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
return (lasterror);
}
return (0);
}
static void
vdev_mirror_close(vdev_t *vd)
{
int c;
for (c = 0; c < vd->vdev_children; c++)
vdev_close(vd->vdev_child[c]);
}
static void
vdev_mirror_child_done(zio_t *zio)
{
mirror_child_t *mc = zio->io_private;
mc->mc_error = zio->io_error;
mc->mc_tried = 1;
mc->mc_skipped = 0;
}
static void
vdev_mirror_scrub_done(zio_t *zio)
{
mirror_child_t *mc = zio->io_private;
if (zio->io_error == 0) {
zio_t *pio;
zio_link_t *zl = NULL;
mutex_enter(&zio->io_lock);
while ((pio = zio_walk_parents(zio, &zl)) != NULL) {
mutex_enter(&pio->io_lock);
ASSERT3U(zio->io_size, >=, pio->io_size);
abd_copy(pio->io_abd, zio->io_abd, pio->io_size);
mutex_exit(&pio->io_lock);
}
mutex_exit(&zio->io_lock);
}
abd_free(zio->io_abd);
mc->mc_error = zio->io_error;
mc->mc_tried = 1;
mc->mc_skipped = 0;
}
/*
* Check the other, lower-index DVAs to see if they're on the same
* vdev as the child we picked. If they are, use them since they
* are likely to have been allocated from the primary metaslab in
* use at the time, and hence are more likely to have locality with
* single-copy data.
*/
static int
vdev_mirror_dva_select(zio_t *zio, int p)
{
dva_t *dva = zio->io_bp->blk_dva;
mirror_map_t *mm = zio->io_vsd;
int preferred;
int c;
preferred = mm->mm_preferred[p];
for (p--; p >= 0; p--) {
c = mm->mm_preferred[p];
if (DVA_GET_VDEV(&dva[c]) == DVA_GET_VDEV(&dva[preferred]))
preferred = c;
}
return (preferred);
}
static int
vdev_mirror_preferred_child_randomize(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
int p;
if (mm->mm_root) {
p = spa_get_random(mm->mm_preferred_cnt);
return (vdev_mirror_dva_select(zio, p));
}
/*
* To ensure we don't always favour the first matching vdev,
* which could lead to wear leveling issues on SSD's, we
* use the I/O offset as a pseudo random seed into the vdevs
* which have the lowest load.
*/
p = (zio->io_offset >> vdev_mirror_shift) % mm->mm_preferred_cnt;
return (mm->mm_preferred[p]);
}
/*
* Try to find a vdev whose DTL doesn't contain the block we want to read
* prefering vdevs based on determined load.
*
* Try to find a child whose DTL doesn't contain the block we want to read.
* If we can't, try the read on any vdev we haven't already tried.
*/
static int
vdev_mirror_child_select(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
uint64_t txg = zio->io_txg;
int c, lowest_load;
ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg);
lowest_load = INT_MAX;
mm->mm_preferred_cnt = 0;
for (c = 0; c < mm->mm_children; c++) {
mirror_child_t *mc;
mc = &mm->mm_child[c];
if (mc->mc_tried || mc->mc_skipped)
continue;
if (mc->mc_vd == NULL || !vdev_readable(mc->mc_vd)) {
mc->mc_error = SET_ERROR(ENXIO);
mc->mc_tried = 1; /* don't even try */
mc->mc_skipped = 1;
continue;
}
if (vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1)) {
mc->mc_error = SET_ERROR(ESTALE);
mc->mc_skipped = 1;
mc->mc_speculative = 1;
continue;
}
mc->mc_load = vdev_mirror_load(mm, mc->mc_vd, mc->mc_offset);
if (mc->mc_load > lowest_load)
continue;
if (mc->mc_load < lowest_load) {
lowest_load = mc->mc_load;
mm->mm_preferred_cnt = 0;
}
mm->mm_preferred[mm->mm_preferred_cnt] = c;
mm->mm_preferred_cnt++;
}
if (mm->mm_preferred_cnt == 1)
return (mm->mm_preferred[0]);
if (mm->mm_preferred_cnt > 1)
return (vdev_mirror_preferred_child_randomize(zio));
/*
* Every device is either missing or has this txg in its DTL.
* Look for any child we haven't already tried before giving up.
*/
for (c = 0; c < mm->mm_children; c++) {
if (!mm->mm_child[c].mc_tried)
return (c);
}
/*
* Every child failed. There's no place left to look.
*/
return (-1);
}
static void
vdev_mirror_io_start(zio_t *zio)
{
mirror_map_t *mm;
mirror_child_t *mc;
int c, children;
mm = vdev_mirror_map_init(zio);
if (zio->io_type == ZIO_TYPE_READ) {
if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) {
/*
* For scrubbing reads we need to allocate a read
* buffer for each child and issue reads to all
* children. If any child succeeds, it will copy its
* data into zio->io_data in vdev_mirror_scrub_done.
*/
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset,
abd_alloc_sametype(zio->io_abd,
zio->io_size), zio->io_size,
zio->io_type, zio->io_priority, 0,
vdev_mirror_scrub_done, mc));
}
zio_execute(zio);
return;
}
/*
* For normal reads just pick one child.
*/
c = vdev_mirror_child_select(zio);
children = (c >= 0);
} else {
ASSERT(zio->io_type == ZIO_TYPE_WRITE);
/*
* Writes go to all children.
*/
c = 0;
children = mm->mm_children;
}
while (children--) {
mc = &mm->mm_child[c];
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset, zio->io_abd, zio->io_size,
zio->io_type, zio->io_priority, 0,
vdev_mirror_child_done, mc));
c++;
}
zio_execute(zio);
}
static int
vdev_mirror_worst_error(mirror_map_t *mm)
{
int c, error[2] = { 0, 0 };
for (c = 0; c < mm->mm_children; c++) {
mirror_child_t *mc = &mm->mm_child[c];
int s = mc->mc_speculative;
error[s] = zio_worst_error(error[s], mc->mc_error);
}
return (error[0] ? error[0] : error[1]);
}
static void
vdev_mirror_io_done(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
mirror_child_t *mc;
int c;
int good_copies = 0;
int unexpected_errors = 0;
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
if (mc->mc_error) {
if (!mc->mc_skipped)
unexpected_errors++;
} else if (mc->mc_tried) {
good_copies++;
}
}
if (zio->io_type == ZIO_TYPE_WRITE) {
/*
* XXX -- for now, treat partial writes as success.
*
* Now that we support write reallocation, it would be better
* to treat partial failure as real failure unless there are
* no non-degraded top-level vdevs left, and not update DTLs
* if we intend to reallocate.
*/
/* XXPOLICY */
if (good_copies != mm->mm_children) {
/*
* Always require at least one good copy.
*
* For ditto blocks (io_vd == NULL), require
* all copies to be good.
*
* XXX -- for replacing vdevs, there's no great answer.
* If the old device is really dead, we may not even
* be able to access it -- so we only want to
* require good writes to the new device. But if
* the new device turns out to be flaky, we want
* to be able to detach it -- which requires all
* writes to the old device to have succeeded.
*/
if (good_copies == 0 || zio->io_vd == NULL)
zio->io_error = vdev_mirror_worst_error(mm);
}
return;
}
ASSERT(zio->io_type == ZIO_TYPE_READ);
/*
* If we don't have a good copy yet, keep trying other children.
*/
/* XXPOLICY */
if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) {
ASSERT(c >= 0 && c < mm->mm_children);
mc = &mm->mm_child[c];
zio_vdev_io_redone(zio);
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset, zio->io_abd, zio->io_size,
ZIO_TYPE_READ, zio->io_priority, 0,
vdev_mirror_child_done, mc));
return;
}
/* XXPOLICY */
if (good_copies == 0) {
zio->io_error = vdev_mirror_worst_error(mm);
ASSERT(zio->io_error != 0);
}
if (good_copies && spa_writeable(zio->io_spa) &&
(unexpected_errors ||
(zio->io_flags & ZIO_FLAG_RESILVER) ||
((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_replacing))) {
/*
* Use the good data we have in hand to repair damaged children.
*/
for (c = 0; c < mm->mm_children; c++) {
/*
* Don't rewrite known good children.
* Not only is it unnecessary, it could
* actually be harmful: if the system lost
* power while rewriting the only good copy,
* there would be no good copies left!
*/
mc = &mm->mm_child[c];
if (mc->mc_error == 0) {
if (mc->mc_tried)
continue;
if (!(zio->io_flags & ZIO_FLAG_SCRUB) &&
!vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL,
zio->io_txg, 1))
continue;
mc->mc_error = SET_ERROR(ESTALE);
}
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset,
zio->io_abd, zio->io_size,
ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE,
ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
}
}
}
static void
vdev_mirror_state_change(vdev_t *vd, int faulted, int degraded)
{
if (faulted == vd->vdev_children)
vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
VDEV_AUX_NO_REPLICAS);
else if (degraded + faulted != 0)
vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
else
vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
}
vdev_ops_t vdev_mirror_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
VDEV_TYPE_MIRROR, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};
vdev_ops_t vdev_replacing_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
VDEV_TYPE_REPLACING, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};
vdev_ops_t vdev_spare_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
VDEV_TYPE_SPARE, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};
#if defined(_KERNEL) && defined(HAVE_SPL)
/* BEGIN CSTYLED */
module_param(zfs_vdev_mirror_rotating_inc, int, 0644);
MODULE_PARM_DESC(zfs_vdev_mirror_rotating_inc,
"Rotating media load increment for non-seeking I/O's");
module_param(zfs_vdev_mirror_rotating_seek_inc, int, 0644);
MODULE_PARM_DESC(zfs_vdev_mirror_rotating_seek_inc,
"Rotating media load increment for seeking I/O's");
module_param(zfs_vdev_mirror_rotating_seek_offset, int, 0644);
MODULE_PARM_DESC(zfs_vdev_mirror_rotating_seek_offset,
"Offset in bytes from the last I/O which "
"triggers a reduced rotating media seek increment");
module_param(zfs_vdev_mirror_non_rotating_inc, int, 0644);
MODULE_PARM_DESC(zfs_vdev_mirror_non_rotating_inc,
"Non-rotating media load increment for non-seeking I/O's");
module_param(zfs_vdev_mirror_non_rotating_seek_inc, int, 0644);
MODULE_PARM_DESC(zfs_vdev_mirror_non_rotating_seek_inc,
"Non-rotating media load increment for seeking I/O's");
/* END CSTYLED */
#endif
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